2&#39;, 4&#39;-dichloro-ortho-benzoyl-benzoic acid and process of making the same



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Patented AprQBO, 1929.

UNITED STATES PATENT OFFICE.

IVAN" GUBELMANN, HENRY J. WEILAND, AND OTTO STALLMANN, OF SOUTH MIL- WA'UKEE, WISCONSIN, ASSIGNORS TO THE NEWPORT GOMIPANY, A CORPORATION Oh DELAWARE.

it, flJDIUHLORO-ORTHO-BENhOli'L-1BENZOIU A1311 AND PBOUESS OF MAKING THE SAME.

Application filed March 28, 192?.

This invention relates to 2, l-dicl1loroortho-henzoyl-henzoic acid and to a process oil malrinp; the same.

ll; is an object of this invention to provide a simple economical method for rendering technically available a valuable starting material tor dyestuti' intermediates.

Uther and further important objects of this invention will hecome more apparent trom the tollowinp; description and appended claims.

W e have now tound that meta-dichlorohentene can he condensed with phthalic anhydride in the presence of a suitahle con- (lensing agent, such as anhydrous aluminum chloride and anhydrous ferric chloride, to give 2', l--dichloro-ortho-henzoyl-henzoic acid. llJe prefer to use anhydrous aluminum chloride for the reason that with that substance as the condensing agent, yields not far from the theoretical are obtained. The smoothness oi this reaction is the more surprising in view of the fact that in. the condensation 01E para-dichlorobenzene with phthalio anhydride, a yield of only 27.2% of theory was obtained. (See journallot American Chemical Society, 1926, p. 3198).

T he reaction loot-ween phthalic anhydride and meta-dichlorohenzene is mostprohahly host expressed by the following equation:

lt appears ohvious to us that the CO group enters into para position to one chlorine atom in the benzene ring and into ortho position to the other'chlorine atom and we attribute the obtaining of'excellent yields to the fact Serial No. 178,807.

that the CO group is not forced into meta position to a chlorine atom.

2, a"-dichloro-ortho-henzoyl-henzoic acid is a white crystalline solid, slightly soluble in hot water and practically insoluble in cold water. lt is soluhle in alcohol, glacial acetic acid, and chlorotorm, and in dilute caustic soda, sodium carbonate solution and am monia.

i2, 4:-dichloro-ortho-henzoyl-henzoic acid can he recrystallized from hot water in the form of white shining crystals. 'After re peated crystallizations the melting point could not he raised about 100-10i U llithout limiting our invention to any particular procedure, the following" example illustrates our preferred method of preparatiou.

ErampZe.-315 parts of dry meta-dichlohcuzene and 74: parts of phthalic anhydride are heated until all is in solution. To this solution is added at -50 0., 157 parts 0st anhydrous aluminum chloride over a period of minutes. This mixture is then heated to IUD-105 C. and held at this temperature until the evolution of hydrochloric acid gas is completed. The dichloro-orthobenzoylhenzoic acid is isolated in a manner similar to that used for other ortho-henzoyl-henzoic acid compounds. The product has a melting point of 100101 (l, and the yield is not far from that theoretically expected.

We are aware that many changes may he made, and numerous details of the process may be varied through a Wide range Without departing from the principles of this invention, and we therefore do not purpose limiting the patent granted hereon, otherwise than necessitated hy the prior art.

We claim as our invention:

1. A process for preparing 2, l-dichloroortho-benzoyl-henzoic acid, which comprises condensing meta-dichloro-benzene and phthalic anhydride.

2. A process for preparing 2, 4-dichloroortha-benzoyl-benzoic acid which comprises treating a mixture of metal-dichloro-benzene dil "I'll ing the following chemical formula:

CO OH all The process of preparing 2, 4llicl1l0rooirlzlio-bcnzoyl-bcnzo' 1 acid, which comprises condensing incm (li-chloi'o benzene and. phlhzilic anhycli'idc in the picscncc 0i anhy- (llOLlS aluminum chloride as COHKlLDSi n5; zigcui by heating the reaction mass to holwccn 100 and 105 (1., and holding within that icnv pci'ii'lui'c mng'c until evolution of l1y(llOCl1ll)- i-ic acid. gas is con'iplel'cil.

in tcstiinony whci'cof We ham hm'cunio .suhsci'ibccl our naincs,

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